Effect of amino acid substitutions at a site of temperature sensitive folding mutation of P22 tailspike protein

Abstract

Twelve different single amino acid substitutions were made at the site of a temperature sensitive folding mutation, TsfU2 (Asp238？Ser), of the phage P22 tailspike protein. Most of the substitutions except Pro and Arg did not affect folding and maturation of the tailspike protein at 28 °C. However, at 39 °C only the wild type residue, Asp, and the Thr substitution allowed the formation of the tailspike trimers. The results suggest that a stereospecific interaction of the residue 238 is required for the folding and maturation of the tailspike, which is ciitical for stabilizing the folding intermediate at high temperature